Yarn feeder

ABSTRACT

A yarn feeder with a friction roller for the yarn, the friction roller being driven with a peripheral speed larger than the yarn speed, which comprises an axle, and a friction roller rotatably mounted on the axle and adapted to loop yarn once about the friction roller. Brake means are provided which have an adjustable braking force. Means are arranged for sensing the yarn tension following the friction roller, and the sensing means is coupled with the brake means such, that an increase of the yarn tension causes a reduction of the braking effect.

United States Patent 1 3,558,026

[72] lm entor Karl lsac J e Rosen 2,115,737 5/1938 Menschner 226/44X 39illagat mn, Sweden 2,353,639 7/1944 Berthold 226/39X [21] .Appl, No,762,073 3,063,229 11/1962 Bonel 226/11X [22] Filed Sept. 24. 1968 [45]Patented Jan. 26, 1971 [32] Priority Sept. 25, 1967 PrimaryExaminerRichard A. Schacher [33] Germany Att0rney-Ernest G. Montague [31 1,635,902

[54] YARN FEEDER 2 Claims 4 Drawing Flgs' ABSTRACT: A yarn feeder with afriction roller for the yarn, [52] US. Cl 226/39, the f i ti rollerbeing driven with a peripheral Speed larger 226/44 than the yarn speed,which comprises an axle, and a friction [51] Int. Cl B6511 23/18 llrotatabb, mounted on the axle and adapted to loop yam [50] Field ofSearch 242/752, Once about the f i i roller Brake means are provided156-1, 1562;226/1139441 195 which have an adjustable braking force.Means are arranged for sensin the am tension followin the frictionroller, and [56] References cued the sensing meai ls is coupled with thebrake means such, that UNlTED STATES PATENTS an increase of the yarntension causes a reduction of the brak- 1,906,211 4/1933 Junker242/75.2X ing effect.

PATENTED JAN26 l9?! Inventor Max YARN FEEDER The present inventionrelates to a yarn feeder. in general. and to such yarn feeder having afriction roller for the yarn. which friction roller can be driven with aperipheral speed which is greater than the' yarn speed and which hasdisposed in front thereofa brake for the yarn. in particular.

In a known yarn feeder of this type. in case of too much friction on thefriction roller. the yarn winds itselfon the friction roller or windstoo fast and thereby the yarn is fed to a position for consumptionwithout tension. for instance. to a knitting position of a knittingmachine. which can lead to appreciable disturbances. and should beavoided by the present brake. 1n order to avoid this. however. thesurface of the friction roller must be sufficiently smooth, in order toovercome always with certainty. the friction between the yarn and thefriction roller also in case of greater tensile stress by the brakingeffect of the brake. and thereby assuring slipping. Since. however,during the feeding of the yarn the braking effect always 'must beovercome, on the unwinding yarn portion a predetermined minimum stressalways must be present. This is. however. not desirable in manyinstances. Each attempt. however. to remove this minimum stress byroughening the surface of the friction roller or by a multiple windingof the yarn about the friction roller again increases the windingdanger.

For this reason. it has already been proposed. that instead of providinga friction roller with a smooth cylindrical surface. rather to arrange acage roller with circular shaped rods having parallel axes. This cageroller has not been accepted in the practice. however. because the rodspromote the formation of downy hair which clogs itself by means of oiland paraffin and. thereby. causes a winding of the yarn on the cageroller.

It is one object of the presentinvention to provide a yarn feeder and afriction roller by which the yarn tension or stress can be maintainedconstant as much as possible. and selectively small at the exit of theyarn feeder. and by which the yarn winding on the friction roller can besafely avoided.

It is another object of the present invention to provide a yarn feeder,in which a brake with an adjustable braking force is provided and inwhich the friction roller has following thereto a member sensing thetensile stress of the yarn. which member is coupled with the yarn brakesuch, that an increase of the tensile stress causes a reduction in thebraking effect. By this arrangement, it is obtained in a surprisinglysimple manner that each time when the yarn adheres so rigidly to thefriction roller that the danger exists that the yarn is wound onto theroller, by this joining of the yarn. a sudden stress reduction is causedin the yarn run behind the friction roller. and thus on the sensingmember. so that by the tension drop of the yarn on the sensing member.the brake immediately pulls stronger and thereby holds back the yarn tosuch a degree that the latter again starts slipping. and a winding ofthe yarn on the friction roller is rendered impossible. Beyond that.however. by the sensing member it is assured that the yarn alwaysemerges from the yarn feeder. in accordance with the present invention.with a substantially constant tension. This tension can be retainedselectively small by a corresponding setting of the return force of thesensing member.

Devices are known for maintaining the tension of a yarn content, whichinclude a sensing member and a brake con trolled by the latter andengaging the yarn in front of the sensing member, Since. however. by theknown yarn feeders with a drivable friction roller, the tension of theyarn emerging from the yarn feeder is likewise maintained constant as arule. it was not obvious to the man skilled in the art to combine thesetwo known devices for maintaining constant the yarn tension together inthe above-described manner.

It is still another object of the present invention to provide a yarnfeeder wherein. in addition to the sensing member formed as a yarnreturn movably disposed against the return force, at least one furtherimmovable yarn return is provided, which forms with the sensing member apulley blocklike arrangement translating the effect of the yarn tensiononto the movement of the sensing member. By such arrangement. it isbrought about in a surprisingly simple manner that the oscillations ofthe sensing member. and thereby the vibrations of the yarn tension. arecompletely avoided. and the tension is maintained very constant.

With these and other objects in view. which will become apparent in thefollowing detailed description. the present invention. which is shown byexample only. will be clearly understood in connection with theaccompanying drawing. in

which; I

FIG. 1 is elevation of one embodiment of a yarn feeder designed inaccordance with the present invention;

FIG. 2 is a top plan view ofthe yarn feeder disclosed in FIG.

FIG. 3 is an elevation of a second embodiment of the yarn feederdesigned in accordance with the present invention; and

FIG. 4 is a top plan view ofthe yarn feeder disclosed in FIG.

Referring now to the drawing. and in particular to FIGS. 1 and 2. theyarn feeder. designed in accordance with the present invention. servesthe purpose of removing a yarn 1. for instance. from a spool not shownof a circular knitting machine and of feeding the same to a system ofthe circular knitting machine. For this purpose. the yarn feeder has afriction roller 5 which can be driven by a drive (not shown) and whichis rotatably mounted for rotation about an axle 3. which friction roller5 is looped around once by the yarn 1. The friction roller 5 is disposedin the run ofthe yarn between a brake 7. having an adjustable brakingforce. and a sensing member 9, sensing the yarn tension and settingaccordingly the braking effect of the brake 7.

The brake 7 comprises in known manner two platelike discs pressedtowards each other by the force of a spring 8, between which discs theyarn l is fed through.

For adjusting of the braking force of the brake 7. a twoarmed lever 13.is swingably mounted about an immovable axle 11. One of the arms 13 ofthe'two-armed lever engages with a wedge-shaped end 17 in known mannerbetween the two plate discs of the brake 7. The lever 13. 15 is retainedby a pulling spring 19 out of engagement on-an abutment (not shown) withthe discs of the brake 7. At the free end of the lever 15. and eye 21 isprovided for sensing the tension of the yarn 1. which eye 21 guides theyarn 1 to the system of the knitting machine.

The operation of the above-described yarn feeder takes place such. thatin case of an increase of the yarn tension, the lever 13. 15 swingsagainst the force of the spring 19 and thereby the brake 7 is released.In case of slight tension increases, it is possible that the frictionroller 5 does not become effective. lf. however. the friction roller5becomes effective. then the tension at the eye 21 drops immediately. sothat the brake 7 becomes effective. and a winding of the yarn on thefriction roller 5 is prevented. One can. therefore. form the surfaceofthe friction roller 5 so rough that. in case ofa predetermined yarntension, the movement of the yarn by the friction roller 5 is alwaysassured.

Referring now again to the drawing, and in particular to the embodimentdisclosed in FIGS. 3 and 4. those parts which cor respond with the partscontained in the embodiment disclosed in FIGS. 1 and 2 are indicatedwith numerals increased by 100. so that in this manner reference can bemade to the description of the previous embodiment.

The embodiment in accordance with FIGS. 3 and 4 differs from thepreviously described embodiment by the fact that instead of the eye 21.two guide rollers 121 and 122 are provided on the lever 113. 115. Inaddition to these two rollers 121 and 122. also there is provided animmovably mounted guide roller 124, which in the run of the yarn 101 isdisposed between the two guide rollers 121 and 122. In addition. thisyarn feeder has in the same manner as in the first embodiment a brake107 and a friction roller 105.

Due to the fact that the yarn 101 runs over the three guide rollers 121.124 and 122. a pulley blocklike arrangement is brought about. by which,upon a swinging out of the lever 113. 115 as a result of tensionincreases. the length of the path of the yarn between these rollers isappreciably reduced so that during each swinging out of the levers [13115 simultaneously, an effect is achieved which reduces the tensionincrease of the yarn. which has the consequence that the yarn tensionincreases more slowly. This slower increase of the yarn tension causeshowever. a very quiet and uniform effect of the tension control by theyarn feeder in accordance with the present invention. So that thereby aswinging of lever 113. llS and thereby also a vibration of the yarntension is avoided with certainty.

This effect, avoiding vibrations and oscillations of the arrangement ofa plurality of yarn guides at the sensing member of the yarn feeder, inaccordance with the present invention, can be easily accommodated by thechoice of a selective number of guide members to all requirementsoccurring in practice. Thus. in many instances, it will suffice if theyarn is guided merely at first about an immovable roller and then abouta roller mounted on the arm 115. It is possible. however to provide morethan three guide rollers in a manner different from that shown in FIG.3, so that thereby a pulley blocklike arrangement with a greatertransmission ratio is obtained.

ln the same manner as in the embodiment disclosed in FIGS. 1 and 2, inwhich a guide roller is used instead of the eye 21, also in theembodiment disclosed in FIGS. 3 and 4 corresponding guide eyes ean beprovided instead of the guide rollers 121, 122 and 124.

The lever l3, 15; 113, 115 can also be used for the purpose to stop thedevices of consumption of the thread I, 101 if the thread 1, l] breaksvin case of a thread break. the lever l3, 113, 115 swings for acomparatively large angle, whereby a control switch can be operated.Particularly of advantage is thereby that, due to the pulley blockeffect, the force of the pulling spring 19, II) can he comparativelylarge, so that also a robust control switch can be operated.

I claim:

1. A yarn feeder with a friction roller for the yarn, said frictionroller being driven with a peripheral speed larger than the yarn speed,comprising:

an axle;

a drivable friction roller in order to feed the yarn rotatably mountedon said axle and adapted to loop yarn at least once about said frictionroller; v

brake means having an adjustable braking force and disposed in front ofsaid friction roller. and acting directly upon a part ofthe yarn runningto said friction roller;

means for adjusting the braking effect of said brake means on said yarn;

means for sensing the yarn tension of the part of the yarn leaving saidfriction roller; and

means for coupling said sensing means with said brake means by means ofwhich with an increase of the tension of the yarn part leaving saidfriction roller, the effect of said brake means on the yarn part runningto said friction roller is reduced.

2. The yarn feeder, as set forth in claim I, where:

said sensing means comprises at least one yarn guide means movablydisposed against a return force, and which includes at least one furtherimmovable guide means; and

said last mentioned immovable guide means forms with said sensing meansa pulley-blocklike arrangement transmitting the effect of said yarntension to the movement of said sensing means.

1. A yarn feeder with a friction roller for the yarn, said frictionroller being driven with a peripheral speed larger than the yarn speed,comprising: an axle; a drivable friction roller in order to feed theyarn rotatably mounted on said axle, and adapted to loop yarn at leastonce about said friction roller; brake means having an adjustablebraking force and disposed in front of said friction roller, and actingdirectLy upon a part of the yarn running to said friction roller; meansfor adjusting the braking effect of said brake means on said yarn; meansfor sensing the yarn tension of the part of the yarn leaving saidfriction roller; and means for coupling said sensing means with saidbrake means by means of which with an increase of the tension of theyarn part leaving said friction roller, the effect of said brake meanson the yarn part running to said friction roller is reduced.
 2. The yarnfeeder, as set forth in claim 1, where: said sensing means comprises atleast one yarn guide means movably disposed against a return force, andwhich includes at least one further immovable guide means; and said lastmentioned immovable guide means forms with said sensing means apulley-blocklike arrangement transmitting the effect of said yarntension to the movement of said sensing means.